Abordagens moleculares no estudo da diversidade microbiana

A importância dos microrganismos na manutenção da vida na Terra é reconhecida por todos. Estes organismos microscópicos são relevantes em áreas tão diversas como a Saúde, Agricultura, Indústria ou Ambiente. O número estimado de todas as espécies é de 100 milhões, das quais 2 milhões foram formalmente descritas. Das cerca de 1,5 a 3,5 milhões de espécies fúngicas que se estimam existir, apenas 5% se encontram descritas. Tradicionalmente, a identificação de espécies de fungos baseia-se no seu isolamento e análise da morfologia das suas estruturas reprodutoras. Embora de grande utilidade, a caracterização morfológica é limitada devido ao reduzido número de caracteres que podem ser analisados, da dependência das condições de cultura e das variações intrínsecas do microrganismo. Actualmente, métodos moleculares baseados na sequenciação do espaçador interno do transcrito de rDNA (ITS) têm vindo a ser utilizados na identificação eficaz de espécies fúngicas. Estudos populacionais têm recorrido à amplificação da região ITS e comparação dos perfis electroforéticos em gradientes desnaturantes (DGGE ou TGGE) de diferentes amostras. Recentemente, o desenvolvimento de técnicas de sequenciação massiva permitiram a emergência de uma nova área- a metagenómica - que pode ser aplicada a comunidades de microrganismos sem a necessidade de os isolar ou cultivar. Este facto adquire especial relevância por se estimar que apenas 17% dos fungos serão capazes de ser cultivados in vitro. Nesta apresentação serão abordados as estratégias que permitiram a evolução da metagenómica. Os desafios da identificação de microrganismos em comunidades serão discutidos, focando o caso particular da diversidade fúngica em amostras de solos.Financiado pela FCT, projecto PTDC/AGR-AAM/099556/200

Vantagens e desvantagens da relação entre plantas e fungos

Apresentação efetuada nas III Jornadas Micológicas, Braga, 2011Os fungos são capazes de estabelecer múltiplas associações/relações com as plantas. Apesar de muitas dessas relações se revelarem prejudiciais, outras apresentam vantagens significativas ao nível do desenvolvimento, nutrição e sanidade das plantas. Nesta comunicação será particularmente abordada a associação sirnbiótica que ocorre entre raízes e fungos do solo - micorrização - referindo-se as vantagens que daí advêm para plantas, fungos e inclusivamente para o Homem

Distinguishing allies from enemies-a way for a new green revolution

Plants are continually interacting in different ways and levels with microbes, resulting in direct or indirect effects on plant development and fitness. Many plant-microbe interactions are beneficial and promote plant growth and development, while others have harmful effects and cause plant diseases. Given the permanent and simultaneous contact with beneficial and harmful microbes, plants should avoid being infected by pathogens while promoting mutualistic relationships. The way plants perceive multiple microbes and trigger plant responses suggests a common origin of both types of interaction. Despite the recent advances in this topic, the exploitation of mutualistic relations has still not been fully achieved. The holistic view of different agroecosystem factors, including biotic and abiotic aspects, as well as agricultural practices, must also be considered. This approach could pave the way for a new green revolution that will allow providing food to a growing human population in the context of threat such as that resulting from climate change.This work was supported by FCT (Fundacao para a Ciencia e a Tecnologia) within the framework of CBMA (UIDB/04050/2020) and CIMO (UID/AGR/00690/2020) I&D centers

Influence of Supplementary Cementitious Materials on Fresh Properties of 3D Printable Materials

The development of printers and materials for 3D Printing Construction during the last two decades has allowed the construction of increasingly complex projects. Some of them have broken construction speed records due to the simplification of the construction process, particularly in non-standard geometries. However, for performance and security reasons the materials used had considerable amounts of Portland cement (PC), a constituent that increases the cost and environmental impact of 3D Printable Materials (3DPM). Supplementary Cement Materials (SCM), such as fly ash, silica fume and metakaolin, have been considered a good solution to partially replace PC. This work aims to study the inclusion of limestone filler, fly ash and metakaolin as SCM in 3DPM. Firstly, a brief literature review was made to understand how these SCM can improve the materials' 3DP capacity, and which methods are used to evaluate them. Based on the literature review, a laboratory methodology is proposed to assess 3DP properties, where tests such as slump and flow table are suggested. The influence of each SCM is evaluated by performing all tests on mortars with different dosages of each SCM. Finally, a mechanical extruder is used to extrude the developed mortars, which allowed us to compare the results of slump and flow table tests with the quality of extruded samples. (c) 2022 by the authors. Licensee MDPI, Basel, Switzerland

Sperm ultrastructure of the honey bee (Apis mellifera) (L) (Hymenoptera, Apidae) with emphasis on the nucleus-flagellum transition region

The flagellum of Apis mellifera (Hymenoptera, Apidae) consists of two mitochondrial derivatives, an axoneme and two accessory bodies. The mitochondrial derivatives are of unequal size and lie parallel to the axoneme. In the larger derivative four regions can be distinguished while in the smaller, only three. The region occurring only in the larger derivative consists of paracystalline material. The smaller mitochondrial derivative terminates anterior to the larger one. An extremely long centriolar adjunct is observed between the nucleus and the smaller mitochondrial derivative. This adjunct is compact, very electron dense and gradually tapers from base toward apex, finishing at the anterior extremity of the axonemal microtubules. In this flagellar region, there is only one accessory body present between the larger mitochondrial derivative and the axoneme. Anteriorly, the tips of the axonemal microtubules are inserted in a well developed mass of granular appearance. This material surrounds the nuclear base, separating it from the anterior end of the larger mitochondrial derivative. We believe that the structure identified here as a centriolar adjunct is homologous to that observed in Formicidae, Ichneumonoidea and Symphyta. Therefore, very probably, it is common to most Hymenoptera

Guarda compartilhada e o principio do melhor interesse da criança

Resumo: Nos últimos anos a guarda dos filhos tornou-se um problema para a sociedade capitalista, pois muitos casais estão rompendo com o seu relacionamento. O objetivo desta monografia é analisar a aplicação da guarda compartilhada após o divórcio e todos os fatos que poderão advir de tal decisão, tendo sempre por interesse melhor atender às necessidades da criança. Neste enfoque foram contemplados diversos assuntos como o histórico da guarda, a evolução legislativa e os tipos de guarda. Outros tópicos também foram tratados, como: o conceito da guarda compartilhada, o benefícios aos filhos, a convivência com os genitores, as vantagens e desvantagens de sua aplicação. É uma ampla pesquisa bibliográfica, além de pesquisa jurisprudencial a respeito do assunto. Por fim, conclui-se que a guarda compartilhada é um ótimo sistema para tratamento dos filhos, evitando danos psicológicos que serão mínimos quando os filhos percebem que têm o direito de conviver com seus pais sabendo que são amados e não terão nenhuma dificuldade de atingir a vida adulto de maneira saudável. O melhor interesse da criança deve sempre ser mantido e o Estado deve intervir para que isso aconteça diante de pais negligente

An improved method for high-quality RNA isolation from needles of adult maritime pine trees

Conventional RNA isolation methods optimised for pine seedlings have been shown to produce poor quality RNA when applied to needles of adult pine trees. We describe here a modified procedure to isolate high pure RNA from needles of thirty-year-old maritime pines, exhibiting high levels of phenolics, polysaccharides and RNases. Major changes were the inclusion of proteinase K in the extraction medium followed by incubation at 42°C. Integrity and purity were evaluated by denaturing gel electrophoresis and by spectrophotometry (A260/A230 and A260/A280). Total RNA could be successfully used for poly(A)+-RNA isolation and cDNA library construction.Fundação para a Ciência e a Tecnologia (FCT) - grant ref. SFRH/BD/3194/2000

As ferramentas de avaliação na Blackboard: um testemunho

Apresentação efectuada no "Seminário de Ensino colaborativo e de e-learning”, em Braga, 2011Partilha da experiência pessoal de avaliação com os recursos disponíveis na plataforma Blackboard. Criação de bancos de questões e os testes. Utilização dos recursos disponíveis no GAE

Molecular aproach on the study of infection of Pinus pinaster Ait. by the fungus Lophodermium seditiosum

Poster apresentado no 10th International Congress on Molecular Plant-Microbe Interactions, Madison, Wisconsin, Estados Unidos da América.The fungi genus Lophodermium comprises several species known to intervene in the degradation process of pine needles. Amongst these species, only L. seditiosum is known to be pathogenic, as it is able to infect healthy needles in young pine populations, spreading from stomata and leading to the death of the needle (needle cast disease). Maritime pine (Pinus pinaster, Ait) is one of the most relevant forest species in SW Europe. Needle cast disease, by attacking young plants, leads to two main events: the lack of self regeneration in natural populations, and complete destruction of pine nurseries. The purpose of our study is to understand the nature of the infection of Pinus pinaster Ait. by L. seditiosum and ultimately gain some knowledge on the overall response of Conipherophyta to infection. As a first step towards this goal, a cDNA library of Pinus pinaster was constructed. Subsequent effort has been directed towards the screening of genes encoding PR proteins involved in host-pathogen interaction, as well as oxidative stress enzymes. In addition, PCR amplification using degenerate primers is in progress in order to allow the identification of putative Resistance genes.Fundação para a Ciência e a Tecnologia (FCT) - grant ref. SFRH/BD/3194/200

Structural and ultrastructural characterization of male reproductive tracts and spermatozoa in fig wasps of the genus Pegoscapus (Hymenoptera, Chalcidoidea)

The three Pegoscapus species present the same internal reproductive tract features comprising testes with a single testicular tubule, seminal vesicles, vasa deferentia, accessory glands and an ejaculatory duct. The seminal vesicle shows two morphologically distinct portions although they do not resemble the separate chambers found in other Chalcidoidea. The anterior portion of the seminal vesicle shows a prominent epithelium and stores the mature spermatozoa, while the posterior region is formed by a thicker muscular sheath that participates on ejaculation. The sexual maturation in Pegoscapus is achieved at emergence, when the testicular degeneration occurs. The spermatozoa of Pegoscapus reveal a basic structure similar to that of other Chalcidoidea. In Pegoscapus sp1. and Pegoscapus sp2. they present the same features, whereas Pegoscapus tonduzi comprises some different characteristics. It measures approximately 160 μm in Pegoscapus sp1. and Pegoscapus sp2., while in P. tonduzi the spermatozoa measure about 360 μm. The extracellular sheath thickness is another difference among the species. While Pegoscapus sp1. and Pegoscapus sp2. show a thick extracellular sheath, in P. tonduzi this sheath is very thin resulting in a large space intervening between the extracellular sheath and the nucleus. Despite these differences, the three species analyzed share some characteristics that allow the establishment of an identity to the spermatozoon of the genus Pegoscapus: the seminal vesicle not divided in chambers; the absence of acrosomal structures in the spermatozoa; the length of the extracellular sheath; the central microtubules being the firsts to terminate in the sequence of microtubular cutoff at the final axonemal portion